1. Field of the Invention
The invention relates to an image-guided surgery system.
2. Description of the Related Art
An image-guided surgery system of this kind is known from U.S. Pat. No. 5,186,174.
An image-guided surgery system is used to visualize a position of a surgical instrument in an operating area within the body of a patient for a surgeon during surgery. Prior to surgery images such as CT or MRI images are made of the patient. The image-guided surgery system includes a position-measuring system for measuring the position of the surgical instrument. The image-guided surgery system also includes a computer for deriving corresponding positions in a relevant image from the positions of the surgical instrument measured. During surgery the position-measuring system measures the position of the surgical instrument relative to the patient and the computer calculates the position in such a prior image which corresponds to the measured position of the surgical instrument. The prior image is then displayed on a monitor, together with the actual position of the surgical instrument. The surgeon can see the position of the surgical instrument in the operating area in the image on the monitor, without him or her seeing the surgical instrument directly. In the image displayed on the monitor the surgeon can thus see how to move the surgical instrument in the operating area without substantial risk of unnecessarily damaging tissue, and notably without risk of damaging vital parts.
An image-guided surgery system of this kind is preferably used in neuro surgery in order to show the surgeon accurately where the surgical instrument is situated in the brain during a cerebral operation.
Using the known image-guided surgery system it is difficult to position the instrument in such a manner that it is oriented in a desired direction with one end in a desired position. In order to move the instrument to the desired position and orientation, it is necessary to move it whereas at the same time the image showing the position of the surgical instrument relative to the patient must be observed so as to determine whether the desired position and orientation have been reached. It has been found that accurate positioning and orientation of the instrument require a substantial amount of training and that these operations remain time-consuming still.